DESCRIPTION: The investigators propose to test the feasibility of developing improved collimators for use with higher performance pixelated detectors under development for use in gamma cameras now under development, as further described by their abstract: "In nuclear medicine, the collimator plays a critical role in the formation of a projection image of the radiopharmaceutical distribution within a patient. The current state-of-the-art of collimator design for Nuclear Medicine has matured, under the assumption that gamma-ray detectors have an intrinsic position dependant Gaussian response function. A fundamental rethinking of collimator design is necessary to optimize collimation for solid state detectors that have a fixed intrinsic rect function response. We will construct design tools by first developing a mathematical model of collimation for detectors with intrinsic pixels and then implement it by computer algorithms. We will conduct experiments to measure performance and validate the simulation tools. Using the validated simulator we will then explore novel collimator designs and hole patterns. We will examine all proposed designs for sensitivity, resolution, cost and manufacture. To advance clinical applications, collimator design will need to keep pace with the anticipated improvements in detector technology. Phase II brings a production prototype of the new collimator design to laboratory and clinical testing." PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE